    $(function(){
        if(!placeholderSupport()){   // 判断浏览器是否支持 placeholder
            $('[placeholder]').focus(function() {
                var input = $(this);
                if (input.val() == input.attr('placeholder')) {
                    input.val('');
                    input.removeClass('placeholder');
                }
            }).blur(function() {
                var input = $(this);
                if (input.val() == '' || input.val() == input.attr('placeholder')) {
                    input.addClass('placeholder');
                    input.val(input.attr('placeholder'));
                }
            }).blur();
        };
    })
    function placeholderSupport() {
        return 'placeholder' in document.createElement('input');
    }




$('.slick').slick({
  dots: true,
autoplay: true,
autoplaySpeed: 5500
});


var clicktag = 0;
 $(".menu-button").click(function(){
        if (clicktag == 0) {
          clicktag = 1;
          $(this).toggleClass("cross");
          $(".nav-down").slideUp("slow");
          $(".nav-click").removeClass("active");
          if($(".nav-list").is(":hidden"))
          {
            $(".nav-list").slideDown("slow");  
          }else{
            $(".nav-list").slideUp("slow");
              }
          setTimeout(function () { clicktag = 0 }, 700);
        }

  }); 
   $(".nav-click").click(function(){
          if($(this).parents("li").find(".nav-down").is(":hidden"))
          {
            $(".nav-click").removeClass("active");
            $(this).addClass("active");
            $(".nav-down").slideUp("slow");
            $(this).parents("li").find(".nav-down").slideDown("slow");  
          }else{
            $(this).parents("li").find(".nav-down").slideUp("slow");
            $(this).removeClass("active");
              }
  });